Plus Gintama also makes a lot of references to several other shounen anime which are derived from the Weekly Shounen Jump magazine and so we need to be familiar with several shounen anime to understand those jokes fully as Darthlord7 told me. So I'd at least wanna watch 25-30 shounen anime fully before attempting to watch Gintama.

Surprisingly, I saw that you watched only 1 episode of DB before dropping it so did you fully get all the parody references? I remember Darthlord7 telling me that a lot of the reference are actually made from DB. Some of those are also made from Yu-Gi-Oh!, Naruto as well as I was told.

it's an action-adveture series with a lot of lighthearted jokes, which can sometimes take a serious/darker turn. The sequel DBZ (Dragon Ball Z) is actually a lot more serious, tense and action-packed in tone; in its essence Z bears a lot of similarities to Naruto.